##### 14.7.3.4 Including heading letters in the index

You can choose whether to include heading letters to introduce each alphabetic section of the index. When IndexNavType=HTML (see §14.7.3.1 Choosing the type of index to generate for HTML), you can also include heading letters across the top of the page, with links to their counterparts within the index:

    [Index]
    ; UseIndexLetters = Yes (default, insert alphabetics) or No
    UseIndexLetters = Yes
    ; IndexLetterSymbol = text to use, or blank to omit
    IndexLetterSymbol = Sym
    ; IndexLetterNumber = text to use, or blank to omit
    IndexLetterNumber = Num
    ; IndexLetterClass = class to use for index letters on left
    IndexLetterClass = IndexLetter
    ; UseIndexTopLetters = Yes (default for IndexNavType=HTML only,
    ; insert top alphabetics that link to left alphabetics) or No
    UseIndexTopLetters = Yes
    ; IndexTopLettersClass = class to use for index letters at top
    IndexTopLettersClass = IndexTopLetters
    ; IndexLetterPrefix = prefix to use for <a name=...>s
    ; for index letters
    IndexLetterPrefix = ixlet
    ; WriteIndexCssLink = Yes (default, write link for index CSS) or No
    WriteIndexCssLink = Yes

When UseIndexLetters=Yes, DITA2Go inserts, as a heading, a letter of the alphabet at the beginning of each section of the index where entries start with that letter.

By default, heading characters are included for entries that start with a digit or with a non-alphanumeric character: for digits, the default heading is Num; and for non-alphanumeric characters, the default heading is Sym. You can change these headings. If you specify a sort order that ignores digits or symbols, you can set IndexLetterNumber or IndexLetterSymbol to blank. See §16.5.8 Customizing index sort order.

When IndexNavType=CSS or IndexNavType=JavaScript, the heading letters are active; activating a heading letter displays all the entries that begin with that letter.

When UseIndexTopLetters=Yes and IndexNavType=HTML, DITA2Go writes the alphabet across the top of the index page. Each letter is an active link to the same heading letter in the body of the index, unless there are no entries that begin with that letter.

The IndexLetterPrefix allows you to create a macro to provide anchors for jumps to the heading letters (which can be several screens apart); for example:

    <p class="IndexLetters"> ...  <a href="#ixletC">C</a>&nbsp; ... </p>

WriteIndexCssLink=No is intended to let you turn off the added CSS links for the index, in case you have custom CSS that already includes them, or in case you add your own in-line styles.

Previous Topic: 14.7.3.3 Specifying CSS classes for index components

Next Topic: 14.7.3.5 Customizing and linking to the index file

Parent Topic: 14.7.3 Configuring index features for HTML output

Sibling Topics:

14.7.3.1 Choosing the type of index to generate for HTML

14.7.3.2 Specifying index file name and heading

14.7.3.3 Specifying CSS classes for index components

14.7.3.5 Customizing and linking to the index file